That is absolutely true and the costs are low compared to “audiophile” cables. However, with Ethernet it has been shown that the interference caused by mode conversion across the entire cable can be better combated with a very high impedance just before the receiver. I also explained this in the article on the choke cable. However, I am not sure whether this is transferable to USB.
I think you ended-up covering the entire length of all the major versions of the throttle cables, e.g. version 1 is a toroid with 8 turns and 5 clip-on ferrites filling the remaining length of the cable. V2 has solely clip-on ferrites along the entire length, each with multiple turns. In V3, 3 toroids with varying turn counts with clip-on ferrites distributed along the full length of the cable.
“Reflections” cause “tuning”, which is what the video refers to. The reflections aren’t perfect, in general. Ideally a cable and its connectors all have uniform impedance, meaning there’s no reflections and so the cable is not tuned (not resonating).
Obviously any ferrites on a cable will make some portion of the cable have a different common mode impedance, when compared to the rest of the cable and also the connectors. So reflections will occur.
In the end, I trust the RF engineer when he says that mismatched impedances at the end of the cable are causing problems with increased common mode noise. Naturally if there’s minimal noise at the tuned frequency to amplify, then the result is innocuous…
You have the equipment to measure these effects, so it’s probably more productive to investigate directly. I can only go on listening tests 🙁
What theory do you have about how the interference can affect the audio signal?
On the one hand, these can certainly get into the analog audio signal in the audio frequency range via demodulations.
On the other hand, they can also cause interference during conversion in the DAC. John Swenson blames the noise in the mass for this.
RF noise, via intermodulation, ends up at audio frequencies as noise. There’s fundamentally no difference between DACs and other hi-fi components that have analogue signals inside them. This is why I have ferrites on the AC power cable for my amplifier.
This video discusses this topic and others:
https://youtu.be/wvfc4UYGDi0?si=nC21HPaDZkaDQx1S
Which interface is used for high-quality audio streaming?
TOSLINK provides optical isolation, but noise and jitter may even increase.
In my hi-fi I use a wi-fi connected streamer (Node) with TOSLINK. Luckily I have 2 TOSLINK inputs.
Modern DACs generally have “perfect” jitter rejection. Chord DACs are basically as good as it gets at rejecting jitter, so it’s not something I worry about. Because I use a Hugo M Scaler, the noise problem I have is mainly caused by the scaler. Unfortunately the fact I don’t use optical between the scaler and my DAC means I have to use lots of “treatment” to minimise RF noise.
The scaler has the two TOSLINK inputs and sends upsampled data over a pair of BNC cables to my DAC. This pair of cables is the only input I use on the DAC.
Jawed